<?xml version="1.0" encoding="UTF-8"?>
<!-- Copyright 2008 XBRL International. All Rights Reserved. -->
<?xml-stylesheet type="text/xsl" href="../stylesheets/functionDefinition.xsl"?>
<function
  xmlns="http://xbrl.org/2008/function"
  xmlns:reg="http://xbrl.org/2008/registry"
  xmlns:xhtml="http://www.w3.org/1999/xhtml"
  xmlns:xfi="http://www.xbrl.org/2008/function/instance" 
  xmlns:xfie="http://www.xbrl.org/2008/function/instance/error" 
  xmlns:xbrli="http://www.xbrl.org/2003/instance" 
  xmlns:xs="http://www.w3.org/2001/XMLSchema"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
  xsi:schemaLocation="
  http://xbrl.org/2008/registry ../schemas/registry.xsd
  http://xbrl.org/2008/function ../schemas/function.xsd
  ">

  <lastUpdated moment="2008-01-30T00:00:00" />

  <owners>
    <reg:owner id="herm">
       <reg:name>Herm Fischer</reg:name>
       <reg:affiliation>UBMatrix / Mark V Systems</reg:affiliation>
       <reg:email>fischer@markv.com</reg:email>
       <reg:assumedOwnership moment="2008-01-23T00:00:00" />
    </reg:owner>
    <reg:owner id="geoff">
       <reg:name>Geoff Shuetrim</reg:name>
       <reg:affiliation>Galexy</reg:affiliation>
       <reg:email>geoff@galexy.net</reg:email>
       <reg:assumedOwnership moment="2008-01-29T00:00:00" />
    </reg:owner>
  </owners>

  <summary>Return the value of an instant period.</summary>

  <documentation>
    <xhtml:p>
    For the dates, XBRL uses a union of date and dateTime. When a date
    is specified, it should be expanded to a dateTime as specified in
    the XBRL specification.
    </xhtml:p>
  </documentation>

  <reference xlink:type="simple" xlink:href="http://www.xbrl.org/Specification/XBRL-RECOMMENDATION-2003-12-31+Corrected-Errata-2006-12-18.htm#_Toc156209161">
    XBRL 2.1 Section 4.7.2
  </reference>

  <signature name="xfi:period-instant">
    <input name="period" type="element(xbrli:period)"/>
    <output type="xs:dateTime">
      <xhtml:p>
        Returns the instant reported by the period if the period is an instant period.
        For an instant date without time, the dateTime returned is is the
        midnight at the end of the date reported, conceptually as if the time portion
        were "T24:00:00".
      </xhtml:p>
    </output>
  </signature>
  
  <error code="xfie:PeriodIsNotInstant">
    <xhtml:p>
      This error MUST be thrown if the period is not an instant.
    </xhtml:p>
  </error>

  <conformanceTest xlink:type="simple" xlink:href="80129 xfi.period-instant testcase.xml"/>

  <revisions>
    <reg:revision on="2008-01-23T00:00:00" by="herm">
      <xhtml:p>
        Created the test.
      </xhtml:p>
    </reg:revision>
    <reg:revision on="2008-01-30T00:00:00" by="geoff">
      <xhtml:p>
        Adapted the syntax to the new format.
      </xhtml:p>
      <xhtml:p>
        Changed the documentation to indicate the nature of the function.
      </xhtml:p>
    </reg:revision>
    <reg:revision on="2008-01-30T00:00:00" by="geoff">
      <xhtml:p>
        Fixed up the sequence type syntax in the function signature.
      </xhtml:p>
    </reg:revision>
    <reg:revision on="2008-01-31T11:28:00" by="geoff">
      <xhtml:p>
        Converted links to XLink syntax suggested by Cliff Binstock.
      </xhtml:p>
    </reg:revision>
    <reg:revision on="2008-03-26T21:23:00" by="herm">
      <xhtml:p>
        Clarified time portion of output when only date is reported, without time.
      </xhtml:p>
    </reg:revision>
  </revisions>

</function>
